(navigation image)
Home American Libraries | Canadian Libraries | Universal Library | Community Texts | Project Gutenberg | Children's Library | Biodiversity Heritage Library | Additional Collections
Search: Advanced Search
Anonymous User (login or join us)
Upload
See other formats

Full text of "Practical Organic Chemistry"

PRACTICAL ORGANIC CHEMISTRY

PREPARATION 48.
Nitrobenzene, C(iH5NO2
Mitscherlich, Annalen, 1834, 12, 305.
50 grms. benzene.
So     „      (60 c.c.) cone, nitric acid, sp. gr. 1*4-
120     „      (60 c.c.) cone, sulphuric acid.
The two acids are mixed and well cooled, and then slowly
added from a tap-funnel to the benzene, which is contained in. • <•
flask (-i- litre). The contents of the flask are well shake ft a.ltcT
each fresh addition. Nitrous fumes are evolved, and a consider-
able amount of heat developed. Care must, however, be taken
that-the temperature does not exceed 50—60° by immersing' tlit*
flask, if necessary, in cold water. The nitrobenzene sepa.rii.tt-s
out as a brouli, oily layer on the surface of the acid licjUH*.
When the acid has all been added, an operation which. l:ii*t^
about half an hour, the mixture is heated for about twenty
minutes on the water-bath, and again well shaken. The con-
tents of the flask, on cooling, are poured into a stoppered sep;i-
rating-funnel, the lower layer of acid removed, and the nitro-
benzene washed free from acid by shaking once with w«ttt*t"
(50 c.c.), then with dilute carbonate of soda solution, and aysiin
with water, the oil being each time withdrawn from the bottom
of the vessel. The nitrobenzene, separated as carefully as pos-
sible from water, is allowed to stand over a few pieces of fused
calcium chloride, and shaken occasionally until the liquid i'.-»
clear. The yellow liquid is decanted, or filtered from tii«^
calcium chloride, and distilled in a distilling-flask, with con-
denser tube only. At first a little benzene passes over ; tlitr
temperature then rises, and the nitrobenzene distils at 204
20f, and is separately collected. The brown residue consist^
of dinitrobenzene, the quantity depending upon whether tilt-
temperature during nitration has been allowed to rise too liiylx.
Yield about 60 grams.
__           CGHG 4- HO.NO3 = C0H5NOo + H2O.
The function of the sulphuric acid is that of a dehydrating*
agent-taking up the water formed in'the reaction.
Properties.—Light   yellow   liquid,   with a   smell   of   bitter